I've heard about using the blue tote for dumping so you don't have to move the rig. When the tote is not as large as the tanks you are dumping from do you just have to wing it and hope you shut it do...
use mine for black and gray. it has 2 back wheels and a metal bar that hooks to the tow ball on the truck.... i just pull it to the dump station, hook up the hose and pull the handle to let it flow!.... no problem!